A role for noradrenaline in pre-eclampsia: towards a unifying hypothesis for the pathophysiology

Developmental expression of catecholamine system in the human placenta and rat fetoplacental unit

Catecholamines norepinephrine and dopamine have been implicated in numerous physiological processes within the central nervous system. Emerging evidence has highlighted the importance of tightly regulated monoamine levels for placental functions and fetal development. However, the complexities of synthesis, release, and regulation of catecholamines in the fetoplacental unit have not been fully unraveled. In this study, we investigated the expression of enzymes and transporters involved in synthesis, degradation, and transport of norepinephrine and dopamine in the human placenta and rat fetoplacental unit. Quantitative PCR and Western blot analyses were performed in early-to-late gestation in humans (first trimester vs. term placenta) and mid-to-late gestation in rats (placenta and fetal brain, intestines, liver, lungs, and heart). In addition, we analyzed the gene expression patterns in isolated primary trophoblast cells from the human placenta and placenta-derived cell lines (HRP-1, BeWo, JEG-3). In both human and rat placentas, the study identifies the presence of only PNMT, COMT, and NET at the mRNA and protein levels, with the expression of PNMT and NET showing gestational age dependency. On the other hand, rat fetal tissues consistently express the catecholamine pathway genes, revealing distinct developmental expression patterns. Lastly, we report significant transcriptional profile variations in different placental cell models, emphasizing the importance of careful model selection for catecholamine metabolism/transport studies. Collectively, integrating findings from humans and rats enhances our understanding of the dynamic regulatory mechanisms that underlie catecholamine dynamics during pregnancy. We identified similar patterns in both species across gestation, suggesting conserved molecular mechanisms and potentially shedding light on shared biological processes influencing placental development.

The role of the placenta-brain axis in psychoneuroimmune programming

Gestational exposures have enduring impacts on brain and neuroimmune development and function. Perturbations of pregnancy leading to placental structure/function deficits, cell stress, immune activation, and endocrine changes (metabolic, growth factors, etc.) all increase neuropsychiatric risk in offspring. The existing literature links obstetric diseases with placental involvement to offspring neuroimmune outcomes and neurodevelopmental risk. Psychoneuroimmune outcomes in offspring brain include changes to microglia, cytokine/chemokine production, cell stress, and long-term immunoreactivity. These outcomes are altered by structural, anti-angiogenic/hypoxic, inflammatory, and metabolic diseases of the placenta. This fetal programming occurs via direct placental passage or production of factors which can act directly on fetal brain substrates, or indirectly via action of circulating factors on intermediates in the placenta. Placental neuroendocrine, vascular/angiogenic, immune, and extracellular vesicular mechanisms are detailed. These mechanisms interact within various placental and pregnancy conditions. An increased understanding of the placental origins of psychoneuroimmunology will yield dividends for human health. Identifying maternal and placental biomarkers for fetal neuroimmune health may also revolutionize early diagnosis and precision psychiatry, empowering patients to make the best healthcare decisions for their families. Targeting placental mechanisms may be a valuable approach for the prevention and mitigation of intergenerational, lifelong neuropathology.

Maternal nutrient restriction and dietary melatonin alter neurotransmitter pathways in placental and fetal tissues

INTRODUCTION

Recent research indicates an important role in the placental fetal brain axis, with a paucity of information reported in large animals. Melatonin supplementation has been investigated as a potential therapeutic to negate fetal growth restriction. We hypothesized that maternal nutrient restriction and melatonin supplementation would alter neurotransmitter pathways in fetal blood, cotyledonary and hypothalamus tissue.

METHODS

On day 160 of gestation, Brangus heifers (n = 29 in fall study; n = 25 in summer study) were assigned to one of four treatments: adequately fed (ADQ-CON; 100% NRC recommendation), nutrient restricted (RES-CON; 60% NRC recommendation), and ADQ or RES supplemented with 20 mg/d of melatonin (ADQ-MEL; RES-MEL). Placentomes, fetal blood, and hypothalamic tissue were collected at day 240 of gestation. Neurotransmitters were analyzed in fetal blood and fetal and placental tissues. Transcript abundance of genes in the serotonin pathway and catecholamine pathway were determined in fetal hypothalamus and placental cotyledon.

RESULTS

Serotonin was increased (P < 0.05) by 12.5-fold in the blood of fetuses from RES dams versus ADQ in the fall study. Additionally, melatonin supplementation increased (P < 0.05) neurotransmitter metabolites and transcript abundance of the monoamine oxidase A (MAOA) enzyme in the cotyledon. In the summer study, plasma dopamine and placental dopamine receptors were decreased (P < 0.05) in RES dams versus ADQ.

DISCUSSION

In conclusion, these data indicate novel evidence of the presence of neurotransmitters and their synthesis and metabolism in the bovine conceptus, which could have greater implications in establishing postnatal behavior.

Functional reorganization of monoamine transport systems during villous trophoblast differentiation: evidence of distinct differences between primary human trophoblasts and BeWo cells

BACKGROUND

Three primary monoamines-serotonin, norepinephrine, and dopamine-play major roles in the placenta-fetal brain axis. Analogously to the brain, the placenta has transport mechanisms that actively take up these monoamines into trophoblast cells. These transporters are known to play important roles in the differentiated syncytiotrophoblast layer, but their status and activities in the undifferentiated, progenitor cytotrophoblast cells are not well understood. Thus, we have explored the cellular handling and regulation of monoamine transporters during the phenotypic transitioning of cytotrophoblasts along the villous pathway.

METHODS

Experiments were conducted with two cellular models of syncytium development: primary trophoblast cells isolated from the human term placenta (PHT), and the choriocarcinoma-derived BeWo cell line. The gene and protein expression of membrane transporters for serotonin (SERT), norepinephrine (NET), dopamine (DAT), and organic cation transporter 3 (OCT3) was determined by quantitative PCR and Western blot analysis, respectively. Subsequently, the effect of trophoblast differentiation on transporter activity was analyzed by monoamine uptake into cells.

RESULTS

We present multiple lines of evidence of changes in the transcriptional and functional regulation of monoamine transporters associated with trophoblast differentiation. These include enhancement of SERT and DAT gene and protein expression in BeWo cells. On the other hand, in PHT cells we report negative modulation of SERT, NET, and OCT3 protein expression. We show that OCT3 is the dominant monoamine transporter in PHT cells, and its main functional impact is on serotonin uptake, while passive transport strongly contributes to norepinephrine and dopamine uptake. Further, we show that a wide range of selective serotonin reuptake inhibitors affect serotonin cellular accumulation, at pharmacologically relevant drug concentrations, via their action on both OCT3 and SERT. Finally, we demonstrate that BeWo cells do not well reflect the molecular mechanisms and properties of healthy human trophoblast cells.

CONCLUSIONS

Collectively, our findings provide insights into the regulation of monoamine transport during trophoblast differentiation and present important considerations regarding appropriate in vitro models for studying monoamine regulation in the placenta.

The placenta-brain-axis

All mammalian species depend on the placenta, a transient organ, for exchange of gases, nutrients, and waste between the mother and conceptus. Besides serving as a conduit for such exchanges, the placenta produces hormones and other factors that influence maternal physiology and fetal development. To meet all of these adaptations, the placenta has evolved to become the most structurally diverse organ within all mammalian taxa. However, commonalities exist as to how placental responses promote survival against in utero threats and can alter the trajectory of fetal development, in particular the brain. Increasing evidence suggests that reactions of the  placenta to various in utero stressors may lead to long-standing health outcomes, otherwise considered developmental origin of health and disease effects. Besides transferring nutrients and gases, the placenta produces neurotransmitters, including serotonin, dopamine, norepinephrine/epinephrine, that may circulate and influence brain development. Neurobehavioral disorders, such as autism spectrum disorders, likely trace their origins back to placental disturbances. This intimate relationship between the placenta and brain has led to coinage of the term, the placenta-brain-axis. This axis will be the focus herein, including how conceptus sex might influence it, and technologies employed to parse out the effects of placental-specific transcript expression changes on later neurobehavioral disorders. Ultimately, the placenta might provide a historical record of in utero threats the fetus confronted and a roadmap to understand how placenta responses to such encounters impacts the placental-brain-axis. Improved early diagnostic and preventative approaches may thereby be designed to mitigate such placental disruptions.

Autonomic Dysfunction in Preeclampsia: A Systematic Review

Background: Preeclampsia (PE) is a major obstetric complication that leads to severe maternal and fetal morbidity. Early detection of preeclampsia can reduce the severity of complications and improve clinical outcomes. It is believed that the autonomic nervous system (ANS) is involved in the pathogenesis of PE. We aimed to review the current literature on the prevalence and nature of ANS dysfunction in women with PE and the possible prognostic value of ANS testing in the early detection of PE.

Methods: Literature search was performed using Medline (1966–2018), EMBase (1947–2018), Google Scholar (1970–2018), BIOSIS (1926–2018), Web of science (1900–2018); CINAHL (1937–2018); Cochrane Library, Cochrane Database of Systematic Reviews, Cochrane Central Register of Controlled Trials (CENTRAL) and Cochrane Methodology Register (1999–2018). Additionally, the reference lists of articles included were screened.

Results: A total of 26 studies were included in the present review presenting data of 1,854 pregnant women. Among these women, 453 were diagnosed with PE, 93.6% (424/453) of which displayed autonomic dysfunction. ANS function was assessed by cardiovascular reflex tests (n = 9), heart rate variability (n = 11), cardiac baroreflex gain (n = 5), muscle sympathetic nerve activity (MSNA) (n = 3), and biomarkers of sympathetic activity (n = 4). Overall, 21 studies (80.8%) reported at least one of the following abnormalities in ANS function in women diagnosed with PE compared to healthy pregnant control women: reduced parasympathetic activity (n = 16/21, 76%), increased sympathetic activity (n = 12/20, 60%), or reduced baroreflex gain (n = 4/5, 80%). Some of these studies indicated that pressor and orthostatic stress test may be useful in early pregnancy to help estimate the risk of developing PE. However, autonomic function tests seem not to be able to differentiate between mild and severe PE.

Conclusions: Current evidence suggests that autonomic dysfunction is highly prevalent in pre-eclamptic women. Among autonomic functions, cardiovascular reflexes appear to be predominantly affected, seen as reduced cardiac parasympathetic activity and elevated cardiac sympathetic activity. The diagnostic value of autonomic testing in the prediction and monitoring of autonomic failure in pre-eclamptic women remains to be determined.

Direct laboratory evidence that pregnancy-induced hypertension might be associated with increased catecholamines and decreased renalase concentrations in the umbilical cord and mother’s blood

Background

Renalase (RNL) is a controversial enzyme as to whether it oxidizes catecholamines (CAs) (as is generally accepted) in the blood or not. CAs (dopamine [DPMN], epinephrine [EPI] and norepinephrine [NEPI]) are associated with hypertension, including pregnancy-induced hypertension, which occurs in 8–10% of all pregnancies. Therefore, the aim of the study was to compare CAs and renalase concentration in (i) normotensive controls (C), (ii) patients with preeclampsia (PE) and (iii) patients with severe preeclampsia (SPE), which is one of the well-known symptoms of hypertension.

Methods

This case-control study involved 90 women divided into three groups – 30 C, 30 PE and 30 SPE – whose age and body mass indexes (BMIs) were similar. A total of 270 blood samples (90 maternal samples, 90 umbilical cord artery samples and 90 umbilical cord vein samples) were obtained. CAs and RNL concentrations of the biological samples were measured by enzyme-linked immunosorbent assay (ELISA).

Results

Comparing the amounts of CAs, RNL and systolic blood pressure (SBP)/diastolic blood pressure (DBP) between healthy control pregnant women and pregnant women with PE and SPE (SBP/DBP was 120/80 mm Hg for C, above 140/90 mm Hg for PE and above 160/110 mm Hg for SPE), the levels of CAs were significantly increased whereas RNL was reduced. The correlation between SBP/DBP and the amount of RNL in pregnant women with PE and SPE was negative.

Conclusions

These novel results are evidence that hypertension seen in PE and SPE is directly related to increased levels of CAs and reduced RNL concentrations. The use of RNL preparations may be preferred in future to prevent maternal and perinatal morbidity and mortality due to pregnancy-induced hypertension.

Human Placenta Expresses α2-Adrenergic Receptors and May Be Implicated in Pathogenesis of Preeclampsia and Fetal Growth Restriction

α₂-Adrenergic receptors (α₂ARs) are G-protein-coupled receptors involved in catecholamine signaling by extracellular regulated protein kinase 1 and 2 (ERK1/2) pathways. We examined placental expression and function of α₂AR subtypes in women with severe preeclampsia (sPE) with and without intrauterine growth restriction (IUGR). Placental biopsies were analyzed from 52 women with i) sPE (n = 8); ii) sPE + IUGR (n = 9); iii) idiopathic IUGR (n = 8); iv) idiopathic preterm birth (n = 16); and v) healthy term controls (n = 11). Expression of α₂AR subtypes (α_2A, α_2B, α_2C) and phospho-ERK1/2 (receptor activation marker) was investigated by immunohistochemistry and/or quantitative real-time RT-PCR. The effects of α_2CAR knockdown on syncytialization (syncytin-1 and -2) and β-human chorionic gonadotropin secretion were examined in BeWo cells stimulated with forskolin. The effects of α₂AR agonist UK 14,304 and specific α_2CAR antagonist were tested, using a trophoblast migration assay. All three α₂ARs were expressed and functionally active in human placenta with site-specific localization. Highest α_2BAR and α_2CAR mRNA expression was identified in sPE + IUGR. α_2CAR knockdown increased expression of syncytin-1 and -2 but decreased secretion of β-human chorionic gonadotropin. UK 14,304 impaired trophoblast migration. The observed α₂AR expression pattern suggests different function for each subtype. α_2CAR modulates trophoblast syncytialization and migration and may carry pathogenic role in sPE + IUGR.

Adrenergic receptor blockade attenuates placental ischemia-induced hypertension

Preeclampsia (PE), a disorder of new-onset maternal hypertension and vascular dysfunction during pregnancy, is thought to be linked to placental ischemia-induced release of prohypertensive factors and reductions of vasoprotective factors in the maternal circulation. Although markers of sympathetic nervous activity are elevated in experimental models of placental ischemia-induced hypertension and women with PE compared with their normal pregnant counterparts, the importance of adrenergic receptor signaling in the development of hypertension in PE is unknown. Therefore, we tested the hypothesis that adrenergic receptor blockade attenuates the development of placental ischemia-induced hypertension in rats. Wistar Hannover rats underwent reduced uterine perfusion pressure (RUPP) or Sham surgeries on gestational day 14. By day 19, mean arterial blood pressure (MAP) was increased in RUPP over Sham rats. Groups of RUPP and Sham pregnant rats received terazosin and propranolol (3 mg/kg per day of each via subcutaneous osmotic minipump) to block α1- and β-adrenergic receptors, respectively, beginning on gestational day 14. Adrenergic blockade significantly attenuated the development of hypertension in the RUPP rats with a slight blood pressure-lowering response in the Sham, normal pregnant rats by day 19. In conclusion, these data implicate that placental ischemia-induced hypertension involves adrenergic receptor signaling to promote increases in blood pressure during PE.

Placental CpG methylation of HPA-axis genes is associated with cognitive impairment at age 10 among children born extremely preterm

A major component of the neuroendocrine system is the hypothalamus-pituitary adrenal (HPA) axis. HPA axis genes are also known to play a role in placental physiology. Thus, disruptions in the signaling of HPA axis-associated genes may adversely impact the placenta as well as fetal development, with adverse consequences for health and development of the child. In support of this, recent studies have shown that placental epigenetic methylation of HPA axis genes has an impact on infant behavior. In this study, we evaluated CpG methylation of 14 placental HPA axis-associated genes from a subcohort (n=228) of the Extremely Low Gestational Age Newborns (ELGAN) cohort in relation to cognitive function in mid-childhood (e.g. 10 yrs). Multivariable logistic regression revealed that placental CpG methylation of 10 HPA-axis associated genes were significantly associated with cognition at age 10. Specifically, placental CpG methylation levels of the glucocorticoid receptor gene, Nuclear Receptor Subfamily Group 3 C Member 1 (NR3C1) and Brain-derived Neurotropic Factor (BDNF) were significantly associated with increased odds in developing moderate/severe adverse cognitive impairment at age 10. Methyl-CpG Binding Protein 2 (MECP2) was the major transcriptional regulator of the ten identified HPA genes. The data suggest that placental CpG methylation is associated with cognitive outcomes in mid-childhood.

Prenatal Selective Serotonin Reuptake Inhibitor Use and Associated Risk for Gestational Hypertension and Preeclampsia: A Meta-Analysis of Cohort Studies

BACKGROUND

To analyze existing cohort studies and provide evidence for the use of prenatal selective serotonin reuptake inhibitor (SSRI) monotherapy and the associated risk of gestational hypertension and preeclampsia.

METHODS

A comprehensive search of English language articles published before 30th April 2017 was conducted on PubMed, EMBASE, and the Web of Science databases. Using data acquired, we summarized the relative risks (RRs) and 95% confidence intervals (CIs) of gestational hypertension and preeclampsia using the random-effects model. Heterogeneity between studies was also assessed with the I² statistic.

RESULTS

Seven cohort studies with 1,108,261 individuals were included for analysis. Compared with nonusers, those undertaking prenatal SSRI monotherapy were more likely to develop gestational hypertension or preeclampsia (summarized RR = 1.21, 95% CI: 1.05-1.40, I² = 71.3%), gestational hypertension (summarized RR = 1.14, 95% CI: 1.00-1.30, I² = 5.7%), and preeclampsia (summarized RR = 1.32, 95% CI: 0.99-1.78, I² = 83.3%). In addition, although subgroup analyses, which were stratified by study design, number of cases, geographic location, duration of SSRI monotherapy, registry databases, and adjustment for potential confounders and risk factors, were consistent with the main findings, not all of these showed statistical significance. No evidence of publication bias was detected.

CONCLUSIONS

Women who receive SSRI monotherapy during pregnancy are at increased risk of gestational hypertension and preeclampsia.

What is precise pathophysiology in development of hypertension in pregnancy? Precision medicine requires precise physiology and pathophysiology

It is widely accepted that placental ischemia is central in the evolution of hypertension in pregnancy. Many studies and reviews have targeted placental ischemia to explain mechanisms for initiating pregnancy hypertension. The placenta is rich in blood vessels, which are the basis for developing placental ischemia. However, is the physiology of placental vessels the same as that of nonplacental vessels? What is the pathophysiology of placental vessels in development of pregnancy hypertension? This review aims to provide a comprehensive summary of special features of placental vascular regulations and the pathophysiological changes linked to preeclamptic conditions. Interestingly, some popular theories or accepted concepts could be based on our limited knowledge and evidence regarding placental vascular physiology, pharmacology and pathophysiology. New views raised could offer interesting ideas for future investigation of mechanisms as well as targets for pregnancy hypertension.

A Dormant Microbial Component in the Development of Preeclampsia

Preeclampsia (PE) is a complex, multisystem disorder that remains a leading cause of morbidity and mortality in pregnancy. Four main classes of dysregulation accompany PE and are widely considered to contribute to its severity. These are abnormal trophoblast invasion of the placenta, anti-angiogenic responses, oxidative stress, and inflammation. What is lacking, however, is an explanation of how these themselves are caused. We here develop the unifying idea, and the considerable evidence for it, that the originating cause of PE (and of the four classes of dysregulation) is, in fact, microbial infection, that most such microbes are dormant and hence resist detection by conventional (replication-dependent) microbiology, and that by occasional resuscitation and growth it is they that are responsible for all the observable sequelae, including the continuing, chronic inflammation. In particular, bacterial products such as lipopolysaccharide (LPS), also known as endotoxin, are well known as highly inflammagenic and stimulate an innate (and possibly trained) immune response that exacerbates the inflammation further. The known need of microbes for free iron can explain the iron dysregulation that accompanies PE. We describe the main routes of infection (gut, oral, and urinary tract infection) and the regularly observed presence of microbes in placental and other tissues in PE. Every known proteomic biomarker of "preeclampsia" that we assessed has, in fact, also been shown to be raised in response to infection. An infectious component to PE fulfills the Bradford Hill criteria for ascribing a disease to an environmental cause and suggests a number of treatments, some of which have, in fact, been shown to be successful. PE was classically referred to as endotoxemia or toxemia of pregnancy, and it is ironic that it seems that LPS and other microbial endotoxins really are involved. Overall, the recognition of an infectious component in the etiology of PE mirrors that for ulcers and other diseases that were previously considered to lack one.

Reduced uterine perfusion pressure decreases functional capillary density in skeletal muscle

The purpose of this study was to examine the functional and structural capillary density in the reduced uterine perfusion pressure (RUPP) model, which when performed during pregnancy is an established animal model of preeclampsia. We hypothesized that the RUPP model would be associated with capillary rarefaction and impaired capillary perfusion, which would be more pronounced in the pregnant state. Female Sprague-Dawley rats (n = 32) were randomized to nonpregnancy (Nonpregnant) or breeding (Pregnant) at 12 wk of age and again to RUPP or SHAM surgeries on gestational day (GD) 14 (or equivalent age in nonpregnant rats). On GD 20 (or equivalent), capillary structure and perfusion of the extensor digitorum longus were imaged using digital intravital video microscopy. Functional videos were analyzed by a blinded observer to measure capillary density, expressed as capillaries per millimeter intersecting three staggered reference lines (200 μm). Flow was scored as the percentage of capillaries having 1) continuous, 2) intermittent, or 3) stopped flow. Total capillary density was not different between groups. There was a main effect of RUPP surgery resulting in decreased continuous flow vessels (P < 0.01) and increased stopped flow (P < 0.01), which was driven by differences between pregnant animals (Continuous flow: pregnant SHAM 80.1 ± 7.8% vs. pregnant RUPP 67.8 ± 11.2%, P < 0.05) (Stopped flow: pregnant SHAM 8.7 ± 3.2% vs. pregnant RUPP 17.9 ± 5.7%, P < 0.01). Our results demonstrate that the RUPP surgery is associated with a decrease in functional capillary density in skeletal muscle that is more pronounced in the pregnant state, which may contribute to the vascular pathophysiology observed in preeclampsia.

Antidepressant medication use, depression, and the risk of preeclampsia

OBJECTIVE

To assess the effects of depression and antidepressant medication use during pregnancy on the risk of preeclampsia.

METHODS

We conducted a retrospective, population-based cohort study that linked automated clinical and pharmacy databases including comprehensive electronic medical records of 21,589 pregnant Kaiser Permanente Northern California members between 2010 and 2012.

RESULTS

The overall risk of preeclampsia was 4.5%. The timing of antidepressant medication exposure was an important factor. A significant increase in the risk of preeclampsia emerged for women with a depression diagnosis who took antidepressant medications during the second trimester compared to women with untreated depression (adjusted relative risk [aRR]: 1.6, 95% CI: 1.06, 2.39) and to women without depression (aRR: 1.70, 95% CI: 1.30, 2.23). Similar associations existed for women who took antidepressant medications, but without depression. In contrast, depressed women with psychotherapy showed no increased risk of preeclampsia compared to women with untreated depression or no depression. There was also a statistically significant relationship between the duration of antidepressant medication use and preeclampsia. The observed association appeared stronger for selective serotonin reuptake inhibitor (SSRI) use, although a nonsignificant trend was also noted for use of norepinephrine-dopamine reuptake inhibitors (NDRIs) and serotonin-norepinephrine reuptake inhibitors (SNRIs).

CONCLUSION

Study findings suggest that antidepressant use during pregnancy may increase the risk of preeclampsia, especially use during the second trimester.

The tryptophan utilization concept in pregnancy

The decrease in maternal plasma total (free + albumin-bound) tryptophan (Trp) during the third pregnancy trimester is attributed to induction of indoleamine 2,3-dioxygenase (IDO). When measured, free [Trp] is increased because of albumin depletion and non-esterified fatty acid elevation. The Trp depletion concept in pregnancy is therefore not supported because of incorrect interpretation of changes in Trp disposition and also for not addressing mouse strain differences in Trp-related responses and potential inhibition of Trp transport by the IDO inhibitor 1-methyl tryptophan. Application of the Trp utilization concept in pregnancy offers several physiological advantages favoring fetal development and successful outcome, namely provision of Trp for fetal protein synthesis and growth, serotonin for signaling pathways, kynurenic acid for neuroprotection, quinolinic acid for NAD⁺ synthesis, and other kynurenines for suppression of T cell responses. An excessive increase in Trp availability could compromise pregnancy by undermining T cell suppression, e.g., in pre-eclampsia.

Psychosocial stress related to the loss of a close relative the year before or during pregnancy and risk of preeclampsia

The role of stress in the pathogenesis of preeclampsia has only been investigated in a few studies, and the findings are not conclusive. We analyzed whether maternal bereavement shortly before or during pregnancy is associated with an increased risk of preeclampsia. We conducted a cohort study of singleton births in Denmark during 1978-2008 and in Sweden during 1973-2006 (n=4 122 490) by linking national population-based registers. Mothers were considered exposed to bereavement if they lost a parent, a sibling, a partner, or a child the year before or during pregnancy (n=124 553). The risk of preeclampsia was slightly increased for women who lost a close relative during the 6 months before conception (odds ratio [OR], 1.14; 95% confidence interval [CI], 1.06-1.23) or during the first trimester of pregnancy (OR, 1.15; 95% CI, 1.03-1.29). Exposure during these periods tended to be more closely related to early preeclampsia (delivery before 34 weeks of gestation; OR, 1.37; 95% CI, 1.12-1.67) than to late preeclampsia (OR, 1.13; 95% CI, 1.06-1.20). The strongest association was observed between loss of a child and early preeclampsia when the exposure window was from 6 months before pregnancy until start of second trimester (OR, 4.03; 95% CI, 2.46-6.61). Our results related to timing of exposure suggest that severe stress may influence early placentation. However, the public health implications of our findings are limited in populations with a low prevalence of severe stress exposures.

Altered expression of norepinephrine transporter and norepinephrine in human placenta cause pre-eclampsia through regulated trophoblast invasion

Objective

We investigated the norepinephrine transporter (NET) expression in normal and pre-eclamptic placentas and analyzed the invasion activity of trophoblastic cells based on norepinephrine (NE)-NET regulation.

Methods

NET and NE expression levels were examined by western blot and enzyme-linked immunosorbent assay, respectively. Trophoblast invasion activity, depending on NE-NET regulation, was determined by NET-small interfering RNA (siRNA) and NET transfection into the human extravillous trophoblast cells with or without NE treatment and invasion rates were analyzed by zymography and an invasion assay.

Results

NET mRNA was expressed at a low level in pre-eclamptic placentas compared with normal placentas and NE concentration in maternal plasma increased significantly in pre-eclamptic women compared to normal pregnant women (p<0.05). NET gene upregulation and NE treatment stimulated trophoblast cell invasion up to 2.5-fold (p<0.05) by stimulating matrix metalloproteinase-9 activity via the phosphoinositol-3-kinase/AKT signaling pathway, whereas NET-siRNA with NE treatment reduced invasion rates.

Conclusion

NET expression is reduced by inadequate regulation of NE levels during placental development. This suggests that a complementary balance between NET and NE regulates trophoblast cell invasion activities during placental development.

Relaxation during pregnancy: what are the benefits for mother, fetus, and the newborn? A systematic review of the literature

Previous studies have reported associations between maternal stress during pregnancy and obstetric outcomes as well as fetal development and neonatal adaptation. These findings highlight the importance of identifying pregnant women who experience severe stress and the need for interventions that commence early in pregnancy. The aim of this study was to review studies that investigated the effects of relaxation techniques during pregnancy, including maternal, fetal, and neonatal outcomes. In addition, studies examining maternal endocrine and physiological alterations were reviewed. PubMed was searched using the following key words: maternal well-being, maternal stress, relaxation techniques, pregnancy, fetal neurobehavior, fetal heart rate, neonatal adaptation, and neonatal behavior. (1) Relaxation had a positive impact on women's emotional state. (2) Pregnancy outcomes improved with fewer admissions to the hospital, fewer obstetric complications, longer gestation, reduction of caesarean sections, and fewer postpartum complications. (3) Fetal heart rate and fetal motor activity were reduced as a result of relaxation and therefore interpreted as improved result. (4) Higher-birth-weight and improved performance on the Neonatal Behavioral Assessment Scale was related to relaxation. (5) Relaxation training was associated with reductions in maternal physiological and endocrine measures. Relaxation during pregnancy is associated with salutogenic effects that include regulation of emotional states and physiology. Relaxation is also associated with positive effects both on fetal behavior and on obstetric and neonatal outcomes. Identifying pregnant women at risk and instituting treatment early in pregnancy could improve obstetric and developmental outcomes for both the mother and her fetus.

Structural capillary rarefaction and the onset of preeclampsia

OBJECTIVE

To estimate if reduced capillary density (ie, capillary rarefaction) precedes the onset of preeclampsia and if it could play a role in its pathogenesis. Capillary rarefaction is a consistent finding in essential hypertension.

METHODS

In this longitudinal cohort study, we recruited 322 consecutive white women, of whom 305 women completed the study. We used intravital video microscopy to measure basal (ie, functional) and maximal (ie, structural) skin capillary densities according to a well-validated protocol and measured plasma angiogenic and antiangiogenic factors. Women were studied at five consecutive predetermined visits.

RESULTS

Preeclampsia occurred in 16 women (mean onset at 35.6±4.8 weeks of gestation), 272 women had normal pregnancies, eight had hypertension, and nine pregnancies were complicated by intrauterine growth restriction. In women with a normal pregnancy, significant reduction in maximal capillary density occurred at 27-32 weeks but had resolved by the puerperium. In contrast, in women who later developed preeclampsia, structural rarefaction was greater and occurred earlier at 20-24 weeks of gestation and persisted into the puerperium. We also found that the change in soluble Endoglin from 11-16 weeks of gestation to 27-32 weeks of gestation was significantly correlated with the change in structural capillary density.

CONCLUSION

Significant structural capillary rarefaction precedes the onset of preeclampsia and could play a role in its pathogenesis.

LEVEL OF EVIDENCE

II.

Physiological reactivity to psychological stress in human pregnancy: current knowledge and future directions

Cardiovascular and neuroendocrine reactivity to acute stress are important predictors of health outcomes in non-pregnant populations. Greater magnitude and duration of physiological responses have been associated with increased risk of hypertensive disorders and diabetes, greater susceptibility to infectious illnesses, suppression of cell-mediated immunity as well as risk for depression and anxiety disorders. Stress reactivity during pregnancy has unique implications for maternal health, birth outcomes, and fetal development. However, as compared to the larger literature, our understanding of the predictors and consequences of exaggerated stress reactivity in pregnancy is limited. This paper reviews the current state of this literature with an emphasis on gaps in knowledge and future directions.

Does hypertensive disorder of pregnancy predict offspring blood pressure at 21 years? Evidence from a birth cohort study

Although few studies found that the offspring of women who experienced preeclampsia have higher blood pressure (BP) at childhood and adolescence, no study has observed whether this association exists for adult offspring. To examine whether maternal hypertensive disorder of pregnancy (HDP) predicts adult offspring BP. We followed a sub-sample of 2608 mother-offspring pairs for 21 years from an original cohort of 7223 singleton infants whose mothers gave birth in Brisbane, Australia between 1981 and 1983. HDP was defined as diastolic BP (DBP) over 90 mm Hg on at least two occasions beyond 20 weeks gestation associated with proteinuria and/or excessive fluid retention. Adult offspring's systolic BP (SBP) and DBP were measured at 21 years. Multivariable regressions were used to examine the independent associations of HDP with offspring BP. Unadjusted regression analysis showed that offspring of women who experienced HDP have 3.46 mm Hg greater SBP and 3.02 mm Hg greater DBP at 21 years. This association remained consistent after adjusting for potential confounding and mediating factors including offspring gender, age, percentile birth weight for gestation, placenta weight and body mass index (BMI) at 21 year, maternal age, education, racial origin, and smoking during pregnancy and their pre-pregnancy BMI. Findings of this study suggest that maternal HDP predicts adult offspring BP.

Neuroendocrine mechanisms in pregnancy and parturition

The complex mechanisms controlling human parturition involves mother, fetus, and placenta, and stress is a key element activating a series of physiological adaptive responses. Preterm birth is a clinical syndrome that shares several characteristics with term birth. A major role for the neuroendocrine mechanisms has been proposed, and placenta/membranes are sources for neurohormones and peptides. Oxytocin (OT) is the neurohormone whose major target is uterine contractility and placenta represents a novel source that contributes to the mechanisms of parturition. The CRH/urocortin (Ucn) family is another important neuroendocrine pathway involved in term and preterm birth. The CRH/Ucn family consists of four ligands: CRH, Ucn, Ucn2, and Ucn3. These peptides have a pleyotropic function and are expressed by human placenta and fetal membranes. Uterine contractility, blood vessel tone, and immune function are influenced by CRH/Ucns during pregnancy and undergo major changes at parturition. Among the others, neurohormones, relaxin, parathyroid hormone-related protein, opioids, neurosteroids, and monoamines are expressed and secreted from placental tissues at parturition. Preterm birth is the consequence of a premature and sustained activation of endocrine and immune responses. A preterm birth evidence for a premature activation of OT secretion as well as increased maternal plasma CRH levels suggests a pathogenic role of these neurohormones. A decrease of maternal serum CRH-binding protein is a concurrent event. At midgestation, placental hypersecretion of CRH or Ucn has been proposed as a predictive marker of subsequent preterm delivery. While placenta represents the major source for CRH, fetus abundantly secretes Ucn and adrenal dehydroepiandrosterone in women with preterm birth. The relevant role of neuroendocrine mechanisms in preterm birth is sustained by basic and clinic implications.

Increased alpha-1 adrenoceptor expression in pregnant rats with subrenal aortic coarctation

The progression of pregnancy is associated with attenuation in vasopressor response to adrenergic agonists. In pregnancy-induced hypertension this attenuation is reverted. It is not known if this reversion involves alpha-1 adrenoceptor expression.

OBJECTIVE

In this work we propose that in pregnant rats with subrenal aortic coarctation there are changes in the expression of alpha-1 adrenergic receptors in the thoracic and abdominal aorta during pregnancy.

METHODS

We used non-pregnant, normal pregnant and pregnant with subrenal aortic coarctation female Wistar rats. Pregnancy-induced hypertension indicators, systolic blood pressure, 24 hours proteinuria, pup weight and maternal weight were measured. Dose response curves to phenylephrine were carried out to determine vascular reactivity along pregnancy. Alpha 1-adrenoceptors were detected from thoracic and abdominal aorta using immunoblot.

RESULTS

Results show significant increases in arterial pressure and proteinuria in pregnant rats with SRAC at the end of the third week. Pregnancy reduces alpha-(1-A, -B) and (-D) adrenoceptor expression and this event is reverted by subrenal aortic coarctation. This phenomenon is more apparent in the abdominal segment of the aorta.

CONCLUSIONS

These findings suggest that subrenal aortic coarctation is a good animal model of pregnancy-induced hypertension and that alpha1-adrenoceptors participate in its physiopathology increasing their expression in a segment-dependent manner.

Monoamine transporters in human endometrium and decidua

BACKGROUND

Monoamines play important roles in decidualization, implantation, immune modulation and inflammation. Furthermore, monoamines are potent vasoactive mediators that regulate blood flow and capillary permeability. Regulation of the uterine blood flow is important both during menstruation and pregnancy. Adequate monoamine concentrations are essential for a proper implantation and physiological development of pregnancy. Unlike most transmitter substances, monoamines are recycled by monoamine transporters rather than enzymatically inactivated. Their intracellular fate is influenced by their lower affinity for inactivating enzymes than for vesicular transporters located in intracellular vesicles. Thus, cells are capable not only of recapturizing and degrading monoamines, but also of storing and releasing them in a controlled fashion.

METHODS

The general objective of the present review is to summarize the role of the monoamine transporters in the female human reproduction. Since the transporter proteins critically regulate extracellular monoamine concentrations, knowledge of their distribution and cyclic variation is of great importance for a deeper understanding of the contribution of monoaminergic mechanisms in the reproductive process. MEDLINE was searched for relevant publications from 1950 to 2007.

RESULTS

Two families of monoamine transporters, neuronal and extraneuronal monoamine transporters, are present in the human endometrium and deciduas.

CONCLUSIONS

New knowledge about monoamine metabolism in the endometrium during menstruation and pregnancy will increase understanding of infertility problems and may offer new pharmacological approaches to optimize assisted reproduction.

Lipid compounds of the umbilical cord vein and their alterations in preeclampsia

The lipid composition of vascular walls changes during development, ageing and pathological processes. Preeclampsia is the most common pregnancy-associated pathological syndrome. It is accompanied by significant remodelling of the extracellular matrix, both in the umbilical cord vessels and in the surrounding Wharton's jelly. Lipids of the umbilical cord have not been extensively studied. Here we evaluate the lipid composition of the umbilical cord vein and its alteration in preeclampsia. Thin layer chromatography and high-performance liquid chromatography were employed for these analyses. It was found that the umbilical cord vein wall, as with most human tissues, contains free fatty acids, mono-, di- and triacylglycerols, free cholesterol and its esters. The characteristic feature is the presence of high amounts of monounsaturated fatty acids, mainly myristoleic acid (C14:1) and oleic acid (C18:1), and polyunsaturated fatty acids, including eicosapentaenoic acid (C20:5) and docosahexaenoic acid (C22:6), which are rather minor lipid components of most human tissues. They exist both in a free form and in a form of acylglycerols and cholesterol esters. Preeclampsia is associated with an increase in the accumulation of free fatty acids, acylglycerols and cholesterol esters in the umbilical cord vein wall, with a proportional reduction in unsaturated fatty acid contents in all the investigated lipid fractions. Total amount of myristoleate was similar to control values. It is suggested that stimulation of lipolysis in maternal tissues increases supply of free fatty acids to foetal blood and promotes the accumulation fatty acids and their esters in some foetal vascular walls.

Intimate partner violence (IPV) and preeclampsia among Peruvian women

OBJECTIVE

Mounting evidence supports the view that intimate partner violence (IPV) is an important cause of maternal mortality. Some, but not all, prior studies suggest that IPV is associated with increased risks of maternal medical conditions such as hypertensive disorders of pregnancy which are leading causes of maternal mortality worldwide. We assessed the relation between IPV and risk of preeclampsia among Peruvian women.

STUDY DESIGN

We conducted a case-control study at two large hospitals in Lima, Peru. Preeclampsia cases were 339 women with pregnancy-induced hypertension and proteinuria (i.e., preeclampsia). Controls were 337 normotensive women. Information concerning women's exposure to physical and emotional violence during pregnancy was collected during in-person interviews conducted after delivery and while patients were in hospital. Odds ratios (OR) and 95% confidence intervals (CI) were estimated from logistic regression models.

RESULTS

The prevalence of IPV was 43.1% among cases and 24.3% among controls. Compared with those reporting never exposure to IPV during pregnancy, women reporting any exposure had a 2.4-fold increased risk of preeclampsia (OR=2.4; 95% CI: 1.7-3.3). The association was strengthened slightly after adjusting for maternal age, parity and pre-pregnancy adiposity (OR=2.7; 95% CI: 1.9-3.9). Emotional abuse in the absence of physical violence was associated with a 3.2-fold (95% CI: 2.1-4.9) increased risk of preeclampsia. Emotional and physical abuse during pregnancy was associated with a 1.9-fold increased risk of preeclampsia (95% CI: 1.1-3.5).

CONCLUSIONS

IPV among pregnant women is common and is associated with an increased risk of preeclampsia. These data support recent calls for coordinated global health efforts to prevent violence against women.

Chlamydia trachomatis infection of human trophoblast alters estrogen and progesterone biosynthesis: an insight into role of infection in pregnancy sequelae

The trophoblast cells are in direct contact with endometrial tissues throughout gestation, playing important early roles in implantation and placentation. The physiologic significance and the operating mechanisms involved in probable altered trophoblast functions following Chlamydia trachomatis infection were investigated to determine if C. trachomatis initiates productive infection in trophoblast, effects of such event on the biosynthesis of cholesterol and its derivatives estrogen and progesterone; and the regulator of the biosynthesis of these hormones, human chorionic gonadotropin. Chlamydia trachomatis exhibited productive infection in trophoblast typified by inclusion formation observed when chlamydia elementary bodies were harvested from trophoblast and titrated onto HEp-2 cells. Assessment of the status of C. trachomatis in trophoblast showed a relative increase in protein of HSP-60 compared with MOMP, features suggestive of chlamydial chronicity. There was a decrease in cellular cholesterol of chlamydia infected trophoblast and a down regulation of HMG-CoA reductase. The levels of estrogen and progesterone were decreased, while the expression of aromatase and adrenodoxin reductase was up regulated. Also, there was a decrease in human chorionic gonadotropin expression. The implications of these findings are that C. trachomatis infection of trophoblast may compromise cellular cholesterol biosynthesis, thus depleting the substrate pool for estrogen and progesterone synthesis. This defect may impair trophoblast functions of implantation and placentation, and consequently affect pregnancy sequelae.

Increased fetal blood pressure response to maternal norepinephrine after pharmacological inhibition of norepinephrine uptake in pregnant sheep

OBJECTIVE

Norepinephrine (NE) is elevated in pregnancies complicated by preeclampsia (PE). Specific uptake of NE by the NE transporter (NET) plays a central role as regulator of NE levels. Expression of NET is reduced in placentas from PE pregnancies. To study adverse fetal effects of reduced NET expression on the placental buffering capacity, the NET was pharmacologically blocked by a specific uptake inhibitor reboxetine.

STUDY DESIGN

We evaluated the effect of NE uptake inhibition on maternal and fetal arterial blood pressure responses to increasing maternal doses of NE in 10 chronically prepared fetal sheep. Arterial blood pressure was monitored continuously during increasing doses of i.v. NE.

RESULTS

NET inhibition increased both fetal and maternal mean arterial blood pressure (p < 0.001, respectively).

CONCLUSION

Reuptake by NET appears to be a mechanism protecting the fetus from NE. A reduced uptake capacity in preeclamptic pregnancies due to reduced NE uptake may lead to increased fetal arterial blood pressure.

Effects of formoterol and BRL 37344 on human umbilical arteries in vitro in normotensive and pre-eclamptic pregnancy

Alterations in vascular responses to beta-adrenoceptor agonists in normotensive pregnancy and pre-eclampsia are not fully understood. Thus, we studied changes in vasodilator responses to beta(2)-adrenoceptor agonist formoterol and beta(3)-adrenoceptor agonist BRL 37344 on umbilical arteries isolated from normotensive (n=12) and pre-eclamptic (n=12) pregnant women. Changes in the relaxant effect of formoterol and BRL 37344 were investigated by measuring isometric tensions in endothelium-denuded strips of umbilical arteries in the presence or absence of metoprolol, ICI 118.551 and SR 59230A (beta(1), beta(2), beta(3)-adrenoceptor antagonists, respectively, 10(-6) mol/L). Effects of formoterol and BRL 37344 on cAMP levels of umbilical arteries were evaluated by radioimmunoassay kits. Formoterol (10(-10)-10(-4) mol/L) and BRL 37344 (10(-10)-10(-4) mol/L) caused concentration-dependent relaxation of the contraction induced by phenylephrine (10(-5) mol/L) in umbilical artery strips isolated from both groups. E(max) values of formoterol and BRL 37344 (for normotensive pregnant women: 87.33+/-0.87 and 53.25+/-1.17 vs. for pre-eclampsia: 73.68+/-1.58 and 43.64+/-1.19, n=12, P>0.05, respectively) were significantly smaller in strips from pre-eclamptic women (P<0.05), with no significant change in pD(2) values. E(max) values of formoterol were significantly higher than those of BRL 37344 in both tissue (P<0.05). ICI 118.551 and SR 59230A, but not metoprolol, antagonized the relaxant effects of formoterol and of BRL 37344 on umbilical artery strips isolated from normotensive and pre-eclamptic pregnant women. Formoterol and BRL 37344 increased cAMP levels in both groups, but less significant in pre-eclamptic strips (P<0.05). These results suggest that the relaxation caused in human umbilical arteries by formoterol and BRL 37344 is mediated by a mixed population of beta(2)- and beta(3)-adrenoceptor subtypes, with contribution of cAMP. Umbilical arteries from subjects with pre-eclampsia showed a weaker beta(2)- and beta(3)-receptor-mediated relaxation to formoterol and BRL 37344, suggesting that the reduced action of formoterol and BRL 37344 may be partly due to a decreased effect of cAMP.

In Vivo Dynamic MRI Measurement of the Noradrenaline-induced Reduction in Placental Blood Flow in Mice

PURPOSE

We developed a new model for in vivo placental perfusion measurements based on dynamic MRI in mice. As noradrenaline has been implicated in the pathogenesis of preeclampsia, we examined whether it reduced placental perfusion in mice, and whether such a reduction could be detected with our MRI model.

MATERIALS AND METHODS

Mice at 16 days of gestation were injected intramuscularly with saline or noradrenaline solution. A conventional gadolinium chelate was then injected IV, and a single-slice T1-weighed 2D Fast SPGR sequence was acquired for 200 s. Signal intensity was measured on all the images and converted into contrast agent tissue concentrations in the maternal left ventricle (input function) and placentas. A one-compartment model was developed using compartmental and numerical modeling software. Mean blood flow (F) was calculated from a transfer constant.

RESULTS

Twenty-six mice were studied, yielding a total of 55 MRI measurements of placental perfusion (29 in the control group and 26 in the noradrenaline group). Mean placental blood flow (F) was significantly lower in the noradrenaline group (0.72+/-0.84 ml/min/g of placenta) than in the control group (1.26+/-0.54 ml/min/g of placenta).

CONCLUSION

Noradrenaline reduces placental perfusion in mice. Our MRI dynamic model might be useful for detecting and investigating abnormal placental blood flow, thereby avoiding the need for invasive procedures and animal sacrifice.

Association between a functional dopamine D4 receptor promoter region polymorphism (-C521T) and pre-eclampsia: a family-based study

Although many candidate genes have been studied in pre-eclampsia (PE), the important class of catecholamine receptors that contribute to sympathetic tone and blood pressure regulation has yet to be investigated. We therefore examined the dopamine D4 receptor (DRD4) gene. We performed a prospective family-based study in 50 families (patient and both her parents) who were genotyped for three DRD4 promoter regions. These single-nucleotide polymorphisms (SNPs) were tested for association using family-based association test (FBAT) that also included two quantitative measures, aspartate aminotransferase [serum glutamic oxalacetic transaminase (SGOT)] and systolic blood pressure. SNPs were assayed using a commercially available SNAPSHOT kit and PCR products were analysed in an ABI 310 DNA analyser. A significant association (preferential transmission of the T allele from a heterozygous parent to affected mother) was observed between the -C521T SNP and PE (P = 0.019). Significant association was also observed between the -521T allele and two-dimensional measures of PE : GOT (P = 0.039) and systolic blood pressure (P = 0.036). The DRD4 promoter region -C521T SNP that reduces transcriptional efficiency of this gene is suggested to contribute to developing PE. Additionally, DRD4 -521 TT homozygosity may be a marker for severe PE.

Maternal preeclampsia predicts elevated blood pressure in 12-year-old children: evaluation by ambulatory blood pressure monitoring

Ambulatory blood pressure (ABP) monitoring offers a reliable method for determining blood pressure (BP) in children. The aim of this cohort study was to examine whether maternal preeclampsia is associated with elevated BP in an offspring. The study population consisted of 57 children born to preeclamptic mothers (PRE) and their 57 age- and sex-matched control subjects born to normotensive mothers (non-PRE). We examined the 24-h ABP at 12 y of age in the PRE and non-PRE children. Within the two groups, the association of anthropometric measures, plasma catecholamine (epinephrine [E], norepinephrine [NE]) concentrations, and ABP was examined. The PRE children had significantly higher mean 24-h systolic and diastolic ABPs than the non-PRE children. The same was true for the mean daytime and nighttime systolic and diastolic ABPs. The PRE boys had higher 24-h systolic ABP than the PRE girls. In the PRE children, high plasma E concentration and being born small for gestational age (SGA) predicted high systolic 24-h ABP in logistic regression analysis. In the non-PRE children, high current body mass index (BMI) and high plasma E concentration was associated with high systolic 24-h ABP. In conclusion, systolic and diastolic ABP values were elevated in the PRE children. High plasma E concentration and being born SGA were associated with high systolic 24-h ABP in the PRE children. Presumably maternal preeclampsia affects offspring via several mechanisms, including genetic ones and metabolic consequences of restricted intrauterine growth.

Stimulation of the ADRB3 adrenergic receptor induces relaxation of human placental arteries: influence of preeclampsia

Preeclampsia, which complicates 3-8% of pregnancies, is one of the leading causes of neonatal morbidity and mortality. Its pathophysiology remains unclear. The aim of the present study was to investigate the presence and the role of beta2- and beta2-adrenergic receptors (ADRB2 and ADRB3, respectively) in human placental arteries and to assess the influence of preeclampsia on ADRB responsiveness. SR 59119A, salbutamol, and isoproterenol (ADRB3, ADRB2, and nonselective ADRB agonists, respectively) induced a concentration-dependent relaxation of placental artery rings obtained from women with uncomplicated or preeclamptic pregnancies. SR 59119A-induced relaxation was unaffected by the blockade of ADRB1 and ADRB2 by 0.1 microM propranolol but was significantly decreased by the blockade of ADRB1, ADRB2, and ADRB3 by 10 microM propranolol. Both SR 59119A and salbutamol were associated with a significant increase in cAMP production that was significantly inhibited by pretreatment with 0.1 microM propranolol only for salbutamol. SR 59119A-induced relaxation (E(max) = 28% +/- 5% vs. 45% +/- 4%, respectively) and cAMP production (2.7 +/- 0.5 vs. 4.9 +/- 0.4 pmol/mg of protein, respectively; P < 0.01) were decreased in arteries obtained from preeclamptic compared to normotensive women. Both ADRB2 and ADRB3 transcripts were expressed at the same level between arteries from normotensive and preeclamptic women. Western blot analysis, however, revealed a decreased expression of the ADRB3 immunoreactive protein in arteries from preeclamptic compared to normotensive women. We suggest the presence of functional ADRB2 and ADRB3 in human placental arteries. Even if preeclampsia is associated with an impairment of the ADRB3 responsiveness, ADRB3 agonists may have future pharmaceutical implications in the management of pregnancy-related disorders.

Preeclampsia: a renal perspective

Preeclampsia is a syndrome that affects 5% of all pregnancies, producing substantial maternal and perinatal morbidity and mortality. The aim of this review is to summarize our current understanding of the pathogenesis of preeclampsia with special emphasis on the recent discovery that circulating anti-angiogenic proteins of placental origin may play an important role in the pathogenesis of proteinuria and hypertension of preeclampsia.

Physiological stress reactivity in human pregnancy—a review

Prenatal maternal stress has been found to have long-lasting effects on the behavioral and physiological development of the offspring. These programming effects on the fetus would be physiologically mediated through heightened and/or abnormal activity of the maternal sympathetic-adrenal-medullary system (SAM) and especially of her hypothalamic-pituitary-adrenocortical axis (HPA-axis). The abnormalities in maternal physiology could be present in her basal functioning, but also in her physiological reactivity to stressors, which constitutes the topic of this paper. This article reviews studies that have used laboratory challenges to study physiological stress reactivity in pregnant women. It concentrates on stress tests designed to produce pain or discomfort, or cognitive and psychological stress, and that assess changes in blood pressure, heart rate and/or cortisol as reactivity measures. The general conclusion is that physiological stress reactivity appears to be dampened during pregnancy. Nonetheless, the physiological responses to laboratory challenges are clearly present and display enough inter-individual variability to enable the study of links between responsivity patterns, psychosocial variables, fetal behavior, pregnancy outcome and offspring development. This paper also looks into the methodological limitations present in the reviewed studies. Options for sound design of stress test protocols are discussed and recommendations for future studies are presented. These methodological points are general and can therefore also be of use for researchers studying human stress reactivity in other populations and ages.

Plasma Adenosine Levels in Peri-Menopausal Women Having Frequent Hot Flushes

BACKGROUND

The effect of hormone replacement therapy (HRT) on plasma adenosine levels was investigated in climacteric women experiencing hot flushes.

METHODS AND RESULTS

Plasma adenosine levels were measured in 13 peri-menopausal women with frequent hot flushes (>5 per day) before and 3-4 months after initiating HRT. Thirteen healthy pre-menopausal, 9 peri-menopausal women with few hot flushes (<1 or 2 per day) and 10 healthy postmenopausal women were enrolled as controls. The average plasma adenosine level in the peri-menopausal women was 0.20+/-0.09 micromol/L, which was significantly higher than in the pre-menopausal (0.12+/-0.07 micromol/L, p<0.05), peri-menopausal with few hot flushes (0.10+/-0.09 micromol/L, p<0.05) and postmenopausal women (0.13+/-0.06 micromol/L, p<0.05). Both the increased adenosine level and the hot flushes were decreased by HRT (plasma adenosine: 0.13+/-0.06 micromol/L).

CONCLUSIONS

Increased plasma adenosine in peri-menopausal women may be associated with frequent hot flushes.

Diurnal blood glucose profiles in women with gestational diabetes with or without hypertension

AIM

The aim of the study was to establish whether diurnal blood glucose profiles differed in women with gestational diabetes (GDM) with different forms of hypertensive complications.

METHODS

The subjects were patients diagnosed at 26-32 gestational weeks as having GDM (n = 178). They were classified as being normotensive, having chronic hypertension (with or without superimposed pre-eclampsia on chronic hypertension) or pregnancy-induced hypertension (with or without proteinuria). We compared diurnal blood glucose profiles (blood glucose taken every 4 h over 24 h) in these three groups.

RESULTS

Hypertension complicated 43% of the women with GDM. The glucose profiles were similar between the three groups, except that in early morning hours (from 04:00 to 08:00 h) blood glucose concentrations increased in mothers with chronic hypertension, whereas they decreased in the normotensive women. In univariate regression analysis, both obesity (BMI > or = 28 kg/m(2)) and chronic hypertension showed significant association with blood glucose rise from 04:00 to 08:00 h, but in a multiple regression model neither showed significant independent effect.

CONCLUSIONS

The rise in blood glucose levels during the early morning hours in women with GDM and chronic hypertension could reflect greater insulin resistance and sympathetic overactivity.

Norepinephrine Transporter (NET), Serotonin Transporter (SERT), Vesicular Monoamine Transporter (VMAT2) and Organic Cation Transporters (OCT1, 2 and EMT) in Human Placenta from Pre-eclamptic and Normotensive Pregnancies

Pre-eclampsia is one of the most common causes of perinatal and maternal morbidity and mortality. High blood pressure and proteinuria are important clinical signs of pre-eclampsia. Sympathetic overactivity and elevated level of circulating vaso active substances, such as monoamines has been shown. Extracellular concentrations of monoamines are normally kept low by specific transporter proteins of which many are expressed in the placenta. In this study we used in situ hybridization and real-time PCR to study the gene expression of monoamine transporters, such as NET, SERT, VMAT2, EMT and OCT1/2, in normal as well as in pre-eclamptic placentae. We demonstrated high expression of NET mRNA in the trophoblast cells of the anchoring villi and a lower expression intensity in the chorionic villi. SERT mRNA was mainly detected in chorionic villi. VMAT2 mRNA was not detected in the central part of the placenta but was present in the spiral arteries of placenta bed biopsies, in cytokeratin positive cells. EMT mRNA was mainly detected in the intra lobular septa and together with OCT1 and OCT2 mRNAs also expressed in scattered cells of placental vessel adventitias. Moreover, quantitative analysis showed a significant lower expression of NET and EMT mRNAs in pre-eclamptic placentae as compared to the control group. A defective gene expression or function of these monoamines transporters might explain the elevated concentrations of monoamines in pre-eclamptic patients. Monoamine transporters may serve as a protective mechanism preventing vasoconstriction in the placental vascular bed and thereby securing a stable blood flow to the fetus.

Pseudopheochromocytoma of Pregnancy

OBJECTIVE

To report a diagnostically challenging case of preeclampsia.

METHODS

We present a case report with clinical, biochemical, imaging, and immunohistochemical findings. In addition, the clinical features of pheochromocytoma during pregnancy are reviewed, and the challenges in distinguishing it from preeclampsia are discussed.

RESULTS

A 33-year-old woman presented at 14 weeks' gestational age with severe hypertension. Evaluation for secondary causes of hypertension were prompted by difficulty controlling the blood pressure and associated symptoms of headache and nausea. Investigations revealed high levels of urinary catecholamines, in conjunction with increased uptake of (111)In-labeled octreotide in the midabdominal area. At 28 weeks' gestation, worsening of blood pressure, high liver enzyme levels, and proteinuria necessitated a cesarean delivery and concomitant hysterectomy. Blood pressure and urinary catecholamine excretion promptly normalized after delivery. Pathologic examination of the uterus and placenta demonstrated no expression of neuroendocrine markers including chromogranin, but the trophoblast demonstrated strong immunostaining for tyrosine hydroxylase. Expression of this rate-limiting enzyme responsible for catecholamine synthesis may have contributed to the pathogenesis of preeclampsia in this patient.

CONCLUSION

This case demonstrates that severe pre-eclampsia may mimic pheochromocytoma.

Blood pressure, serum lipids, fasting insulin, and adrenal hormones in 12-year-old children born with maternal preeclampsia

Women with prior preeclamptic pregnancies have an increased risk for metabolic syndrome and cardiovascular diseases. Maternal preeclampsia has been associated with elevated blood pressure (BP) in offspring during childhood. The aim of our study was to determine whether elevated BP pressure and metabolic changes, such as dyslipidemia, insulin resistance, and increased adrenal hormonal activity, are found in 12-yr-old children of preeclamptic mothers. Sixty children born after preeclamptic pregnancy (PRE) and 60 matched control subjects born after normotensive pregnancy (non-PRE) were studied at the age of 12 yr. The case-control pairs were matched for sex, gestational age (+/-1 wk), and size at birth. We measured BP and concentrations of blood glucose, serum fasting insulin, total and high density lipoprotein cholesterol, triglycerides, cortisol, dehydroepiandrosterone sulfate, and plasma epinephrine (E) and norepinephrine (NE). Low density lipoprotein cholesterol was calculated according to the Friedewald-Fredrickson formula. The PRE children had significantly higher mean systolic (116.4 vs. 113.2 mm Hg; P = 0.021) and diastolic (73.9 vs. 70.3 mm Hg; P = 0.022) BP than the non-PRE children, even when adjusted by current weight and height. At 12 yr of age, systolic BP values correlated inversely with birth weight (r = -0.459; P < 0.001) and length SD scores (r = -0.429; P = 0.001) in the PRE children. The mean concentrations of serum total, low density lipoprotein, and high density lipoprotein cholesterol; triglycerides; fasting insulin; blood glucose; serum cortisol; and dehydroepiandrosterone sulfate did not differ between the PRE and non-PRE groups. However, the mean plasma E concentration was higher in the PRE than in the non-PRE children (0.32 vs. 0.28 nmol/liter; P = 0.042), whereas the mean NE concentration did not differ between these two groups. In conclusion, 12-yr-old children born with maternal preeclampsia had elevated systolic and diastolic BPs and slightly increased E levels in the circulation. It is not known whether these changes are caused by genetic factors or by preeclampsia itself.

Stress-related preeclampsia: an evolutionary maladaptation in exaggerated stress during pregnancy?

The authors hypothesize that preeclampsia is a stress-related disease and an evolutionary maladaptation of exaggerated stress during human pregnancy. Epidemiologic studies show that relative risk for preeclampsia is increased in many stressful situations. Many risk factors for preeclampsia are stress-related. Low-stress situations, on the contrary, are protective. Stress in pregnancy corroborates all physiopathologic theories for preeclampsia; it does not contradict them. Animals exposed to intense stress show many characteristics of preeclampsia, and some animal models for human preeclampsia have been proposed. The stress-alarm reaction is protective for survival in animals. But the evolutionary maladaptation of this intense stress could lead to preeclampsia in humans.

Skin capillary density changes in normal pregnancy and pre-eclampsia

BACKGROUND

Many abnormalities are known to occur in the microcirculation in essential hypertension, including reduction in capillary density or rarefaction. Peripheral vasodilatation and angiogenesis are critical components of the physiological adaptation in normal pregnancy.

OBJECTIVE

To investigate the hypothesis that defective angiogenesis, reflected in capillary rarefaction, may be implicated in the clinical syndrome of pre-eclampsia.

METHODS

We used intravital capillary video-microscopy to study functional (baseline) and structural (after maximization with venous congestion) skin capillary density in 22 healthy normotensive pregnant women and compared our findings with those in 22 non-pregnant age-matched healthy controls and 11 women whose pregnancies were complicated by pre-eclampsia.

RESULTS

We found that both functional and structural capillary density increased during normal pregnancy. Capillary density in pre-eclamptic women was significantly lower both at baseline and after maximization. Skin capillary density appeared to be inversely correlated with blood pressure during pregnancy and in pre-eclampsia.

CONCLUSIONS

A low capillary density may account, in part, for the failure of blood pressure to decrease in pre-eclamptic pregnancies, and may reflect the maladaptive cardiovascular response that is part of the pre-eclampsia syndrome.

Stress in pregnancy: a new Wistar rat model for human preeclampsia

OBJECTIVE

Our study evaluated the effects of chronic and/or acute stress on pregnant and nonpregnant female rats.

STUDY DESIGN

The rats were exposed to the sonic stimulus associated with overpopulation between days 7 and 14 of pregnancy. The rats were immobilized 2 days before the vascular reactivity experiments.

RESULTS

In 14-day pregnant rats, chronic stress led to lower weight, increased adrenal weight, lower endothelium-derived relaxing factor release, and lower fetal weight. In 20-day pregnant rats, chronic stress caused decreased weight gain, higher blood pressure, increased vasomotility and proteinuria, lower endothelium-derived relaxing factor release, and lower fetal weight. In the 20-day pregnant group, the higher adrenal weight resulted in higher blood pressure, lower vascular relaxation, and lower average fetal weight. A greater number of fetuses had higher adrenal weight, higher blood pressure, and lower vascular relaxation.

CONCLUSION

The alterations found in the rats were similar to those that occur in human preeclampsia. Therefore, we propose a new animal model for human preeclampsia.

Apolipoprotein E polymorphism in South African Zulu women with preeclampsia

OBJECTIVES

Apolipoprotein E may contribute to the hypertiglyceridemia and consequent endothelial dysfunction of preeclampsia. We carried out a study to determine whether the apolipoprotein E genotype plays any role as a risk factor for preeclampsia in a black South African population with a high incidence of preeclampsia.

DESIGN

A descriptive, prospective study design was used.

SETTING

King Edward VIII Hospital, a tertiary care, referral academic hospital in Durban, South Africa.

PATIENTS AND PARTICIPANTS

One hundred three South African Zulu women with preeclampsia and 110 healthy normotensive women attending the antenatal clinic were recruited.

MAIN OUTCOME MEASURES

The relationship between the apolipoprotein E allele and genotype frequencies to preeclampsia as well as adverse perinatal outcome.

RESULTS

The frequencies of varepsilon2 and varepsilon4 alleles (0. 19 and 0.25, respectively) were much higher than those reported in other population groups. However, there was no significant difference in the apolipoprotein E genotype and allele frequencies between the study and the control groups. The varepsilon2/2 genotype was associated with increased risk of perinatal death (p = 0.047).

CONCLUSION

The study suggests that, despite the high incidence of both preeclampsia and the varepsilon2 and varepsilon4 alleles in South African Zulu women, apolipoprotein E genotype does not appear to be a risk factor for preeclampsia in this population.